Elements and Compounds

What You'll Learn

Elements are pure substances made of only one type of atom. Compounds are substances made of two or more elements chemically bonded in fixed ratios.

Key Words

exothermic
reactant

Steps

Step 1 — Read

Look at the vocabulary words and write a definition for each in your own words.

Step 2 — Do

Mix baking soda and vinegar in a sealed bag. Weigh the bag before and after. Did the mass change? Explain why or why not using the law of conservation of mass.

Step 3 — Observe

Observe what happens and describe it in detail.

Step 4 — Record

Record your observations in your science journal with measurements and descriptions.

Check Your Understanding

Question 1

1 of 3

What is a compound?